Implement from_json and to_json

src/built_in_functions/data_formats.rs

@@ -0,0 +1,35 @@
+use crate::{BuiltInFunction, Error, Map, Result, Value};
+
+pub struct FromJson;
+
+impl BuiltInFunction for FromJson {
+    fn name(&self) -> &'static str {
+        "from_json"
+    }
+
+    fn run(&self, arguments: &[Value], _context: &Map) -> Result<Value> {
+        Error::expect_built_in_function_argument_amount(self, 1, arguments.len())?;
+
+        let json_string = arguments.first().unwrap().as_string()?;
+        let value = serde_json::from_str(&json_string)?;
+
+        Ok(value)
+    }
+}
+
+pub struct ToJson;
+
+impl BuiltInFunction for ToJson {
+    fn name(&self) -> &'static str {
+        "to_json"
+    }
+
+    fn run(&self, arguments: &[Value], _context: &Map) -> Result<Value> {
+        Error::expect_built_in_function_argument_amount(self, 1, arguments.len())?;
+
+        let value = arguments.first().unwrap();
+        let json_string = serde_json::to_string(&value)?;
+
+        Ok(Value::String(json_string))
+    }
+}

src/built_in_functions/mod.rs

@@ -1,13 +1,16 @@
 use crate::{Map, Result, Value};
 
 mod assert;
+mod data_formats;
 mod fs;
 mod output;
 mod r#type;
 
-pub const BUILT_IN_FUNCTIONS: [&dyn BuiltInFunction; 7] = [
+pub const BUILT_IN_FUNCTIONS: [&dyn BuiltInFunction; 9] = [
     &assert::Assert,
     &assert::AssertEqual,
+    &data_formats::FromJson,
+    &data_formats::ToJson,
     &fs::Read,
     &fs::Write,
     &fs::Append,